Chụp ảnh bằng Camera Intent trong Android Kotlin

Giới thiệu

Ví dụ này minh họa cách chụp ảnh sử dụng Intent hệ thống (MediaStore.ACTION_IMAGE_CAPTURE) và hiển thị kết quả lên ImageView trong Android Kotlin.

Các bước thực hiện

Bước 1: Tạo dự án mới

Mở Android Studio, chọn File → New Project, điền thông tin.

Bước 2: Giao diện (res/layout/activity_main.xml)

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="https://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="4dp">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@id/imageView"
        android:layout_centerInParent="true"
        android:layout_marginBottom="10dp"
        android:text="Click button to take photo from camera"
        android:textAlignment="center"
        android:textColor="@android:color/holo_purple"
        android:textSize="16sp"
        android:textStyle="bold" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_above="@id/btnCaptureImage"
        android:layout_marginTop="16dp"
        android:scaleType="centerCrop"
        android:src="@drawable/ic_baseline_image_24" />

    <Button
        android:id="@+id/btnCaptureImage"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:text="Capture Image" />

</RelativeLayout>

Bước 3: MainActivity.kt

import android.Manifest
import android.content.ContentValues
import android.content.Intent
import android.content.pm.PackageManager
import android.net.Uri
import android.os.Bundle
import android.provider.MediaStore
import android.widget.Button
import android.widget.ImageView
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.core.app.ActivityCompat
import androidx.core.content.ContextCompat

class MainActivity : AppCompatActivity() {
    private lateinit var button: Button
    private lateinit var imageView: ImageView
    private var imageUri: Uri? = null

    private val permissionCode = 1000
    private val imageCaptureCode = 1001

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        title = "KotlinApp"

        imageView = findViewById(R.id.imageView)
        button = findViewById(R.id.btnCaptureImage)

        button.setOnClickListener {
            if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA)
                != PackageManager.PERMISSION_GRANTED
            ) {
                ActivityCompat.requestPermissions(this, arrayOf(Manifest.permission.CAMERA), permissionCode)
            } else {
                openCamera()
            }
        }
    }

    private fun openCamera() {
        val values = ContentValues().apply {
            put(MediaStore.Images.Media.TITLE, "New Picture")
            put(MediaStore.Images.Media.DESCRIPTION, "From Camera")
        }
        imageUri = contentResolver.insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values)

        val cameraIntent = Intent(MediaStore.ACTION_IMAGE_CAPTURE).apply {
            putExtra(MediaStore.EXTRA_OUTPUT, imageUri)
        }
        startActivityForResult(cameraIntent, imageCaptureCode)
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<String>,
        grantResults: IntArray
    ) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        if (requestCode == permissionCode) {
            if (grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                openCamera()
            } else {
                Toast.makeText(this, "Camera permission denied", Toast.LENGTH_SHORT).show()
            }
        }
    }

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)
        if (requestCode == imageCaptureCode && resultCode == RESULT_OK) {
            imageUri?.let { uri ->
                imageView.setImageURI(uri)
            }
        }
    }
}

Bước 4: AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="https://schemas.android.com/apk/res/android"
    package="com.example.q11">

    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"
        android:maxSdkVersion="28" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <provider
            android:name="androidx.core.content.FileProvider"
            android:authorities="${applicationId}.fileprovider"
            android:exported="false"
            android:grantUriPermissions="true">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/file_paths" />
        </provider>

    </application>
</manifest>

Lưu ý: Cần tạo file res/xml/file_paths.xml cho FileProvider (Android 7+). Hoặc dùng MediaStore như ví dụ trên để tránh FileProvider.

Chạy ứng dụng

⚠️ Chỉ test trên thiết bị thật. Kết nối thiết bị, nhấn Run. Nhấn "Capture Image", cho phép quyền, chụp ảnh → ảnh hiển thị trên ImageView.